In the development, repair or remanufacture of motor controls for motors which produce feedback signals indicative of the motor response, it is desirable to test the controls by evaluating the feedback response to control signals for normal operation as well as for motor fault conditions. For example, electronic climate control systems for automotive vehicles rely on such motors for operation of heating, ventilation and air control distribution. Some vehicle seat positioning systems also utilize this type of motor. The motors each incorporate a potentiometer which produces an analog feedback signal which indicates motor position or the position of the device driven by the motor. The control system then uses the information to determine the position of such devices to assist in deciding whether device adjustment is desirable or to establish whether the device or motor has reached a commanded position. It is necessary to accurately emulate all possible conditions of the motor feedback signal to the motor controller in various testing situations including product design, development, evaluation, manufacturing, quality assurance, and repair to verify product operation.
When developing or remanufacturing such controls it has been the practice to employ a motor of the appropriate type which is driven by the control and to monitor its feedback signal to determine the motor response. Since there are many types of such motors with different operating parameters, it is necessary to acquire many motors for test purposes as well as an inventory of back up motors in case of motor failure; maintenance of all those motors is also required. Moreover the use of actual motors limits the direct control or manipulation of the feedback signal required for comprehensive testing and evaluation of each controller. Another shortcoming is that known motor fault conditions are impossible to reproduce for diagnosis or testing of the controllers.
Another known practice tests motor control systems without actual motors: complex software is used to adjust an artificial motor feedback signal by monitoring the motor control voltages. The main problems with this approach are 1) the resolution and slope response of the feedback signal are sub-standard due to the complexity of software calculations, 2) product test time is increased by approximately 35% due to the software overhead required to generate the feedback signal, and 3) the test software design time may be increased by up to 20% since the software must by tailored to each motor type.